Is it possible to for a device with the ip address and Vlan 100 to communicate with an other device with the ip address and Vlan 200 with the following architectures

Senario 1: 1 Layer 3 Switch, 1 Unmanaged Switch, 2 Ethernet cables between the switches

Senario 2: 1 Layer 3 Switch, 1 Managed Switch, 1 Ethernet cables between the switches

There are a couple more scenarios but I think the point it made.

  • The short answer is Yes, if configured correctly. You need a router or L3 switch to route between the two subnets. IF you provide more details, such as a a topology diagram and device information, we can provide more details
    – Ron Trunk
    May 15 '18 at 17:43
  • Did any answer help you? if so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you could post and accept your own answer.
    – Ron Maupin
    Dec 31 '20 at 4:36

VLANs separate L2 traffic - you need the router/L3 switch to enable L3 communication between the VLANs.

The unmanaged switch you can only use for one of the VLANs as it can't separate traffic. For two VLANs you'll need two unmanaged switches.

You cannot connect an unmanaged switch with two cables: using one cable/uplink for each VLAN effective bridges the VLANs, creating a single one again. Connecting two ports from the same VLAN creates a bridge loop, bringing down the network (unless the L3 switch detects this and blocks one of the ports).


With Senario 2 devices mentioned requirement is feasible

  1. 1 layer3 switch 2 ) managed layer2 switch .

Switch virtual interfàce (SVI) are created with Vlans and ip routing need to be configured enabling inter-Vlan routing in layer3 switch allow 2 different VLANs can communicate

Further connect managed switch and layer3 switch with trunk link allowing both Vlans on trunk link .

And further connect end host with managed switch ports allowing access port and tagging specific Vlans .


i dont think even with native vlan it could be possible.

if you could set one of the vlan's on un-managed switch, then you can put other vlan on native vlan and it will be possible with one cable.

with two cable you will have native vlan mismatch or stp loop.

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